Summary C-GKGM, a BA3112 operating as Corpac Canada Ltd. (CorporateExpress) CPB888, was en route under instrument flight rules from Fort McMurray, Alberta, to Calgary International Airport, Alberta. C-FDMR, a SA227DC operating as Alta Flights (ChartersInc.) CNS213, was en route, also under instrument flight rules from Calgary International Airport to Edmonton City Centre Airport, Alberta. Because of extensive thunderstorm activity between Edmonton and Calgary and the restricted airspace associated with the G-8 Conference at Kananaskis, Alberta, both aircraft were diverted east of their flight planned routes. At 1610 mountain daylight time, approximately 60nautical miles southeast of Edmonton International Airport, the aircraft met on a nearly reciprocal heading at an altitude of 16000feet above sea level. They had vertical separation of 200feet and lateral separation of 1.3nautical miles in an area where 1000feet or 5nautical miles is required. The aircraft passed in cloud and neither crew saw the other aircraft. Ce rapport est galement disponible en franais. Other Factual Information Both aircraft were being controlled by the Edmonton Area Control Centre (ACC). The loss of separation took place in the Red Deer sector of the Calgary en route specialty. CPB888 was flight planned at an altitude of 16000feet above sea (asl) and given a heading of 175 magnetic to intercept the 354 radial of the Calgary VOR. This heading resulted in a track of about 164 because of westerly winds. Control was handed off to the Edmonton departure sector, and then to the Red Deer en route sector. The aircraft remained at 16000feet. CNS213 was flight planned from Calgary to Edmonton via V112 to the Edmonton VOR at 16000feet and proceeded at an initial altitude of 14000feet asl. Five minutes before the occurrence, the Red Deer sector radar controller cleared CNS213 to maintain 16000 feet,. When the two aircraft were about 4.2nautical miles apart, the Edmonton terminal arrival controller noticed the conflict and drew it to the attention of the Red Deer data controller by land line. The data controller then verbally relayed this information to the Red Deer radar controller who instructed CNS213 to descend immediately to 15000feet. During their scanning of flight progress strips and the radar display, the Red Deer en route sector controllers did not detect the conflict between the aircraft. Neither aircraft was fitted with a traffic alert and collision-avoidance system (TCAS), nor were they required to be by Canadian regulations. There was no ground-based conflict alert system in operation in Edmonton ACC at the time of the occurrence. Airmet C1, a short term weather advisory issued at 1459 mountain daylight time1, warned of a line of scattered cumulonimbus clouds developing in a line from northwest of Red Deer to southwest of Calgary, moving northeastward at about 10knots. The cells were expected to strengthen, especially northeast of Calgary with tops expected to rise to between 38000 and 45000feet. For the three-day duration of the G-8 Conference at Kananaskis, ClassF restricted airspace (CYR255) was established to prevent unauthorized aircraft from entering the area. CYR255 was an irregularly shaped area with an approximate 80nautical mile radius around the conference site. (SeeAppendixA-OccurrenceDiagram). Aircraft travelling west from Calgary had to be routed around the northeast corner of CYR255 in the Red Deer en route sector before proceeding west. Civilian flights were only to be allowed into the restricted area in emergency situations, and unauthorized aircraft penetrating the restricted area were at risk of being intercepted by military fighters. A supervisor at the Edmonton ACC was assigned the role of G-8 Airspace Coordinator to liaise between the military and the ACC in the planning and management of G-8 restricted airspace. The coordinator completed his shift and left the ACC 40minutes before the occurrence. No replacement was scheduled. Aircraft flying between Edmonton and Calgary diverted east around the thunderstorm activity, and because of traffic volumes at Calgary, four inbound aircraft were instructed to hold short of Calgary terminal airspace for up to 20minutes. With 13aircraft operating in the Red Deer sector at the time of the occurrence, the traffic level was considered to be from moderate to high, with high complexity. To deal with the anticipated workload associated with G-8 activities, the normal contingent of eight controllers working the Calgary en route sectors was increased to11. At the time of the occurrence, eight controllers were active, while three were on breaks. The Red Deer en route sector was staffed by two controllers. A radar controller directed traffic flow within the sector by monitoring the radar display and handling communications with aircraft, and a data controller assisted the radar controller by administering flight progress strips and handling land line communications. During the 34minutes preceding the incident, the Red Deer en route sector radar controller was involved in 311communications by radio or land line in addition to unrecorded conversations between the two controllers. Flight crews reported that based on the number of radio transmissions, the Red Deer sector was very busy. At the time of the occurrence, the supervisor responsible for the Calgary en route specialty was working a controller position which was physically located directly behind the Red Deer sector. Supervisor duties included maintaining awareness of traffic situations, managing personnel, including breaks and, in conjunction with the shift manager, facilitating decisions on flow control implementation. Supervisors were also required to periodically work in control positions in order to maintain their qualification as controllers. Both the radar and data controllers were licensed and current in accordance with existing regulations. The radar controller had 29 years of experience, with 14years in the Calgary en route specialty. On the day of the occurrence, he reported for work at 0815 with the incident occurring about eight hours after the beginning of his shift, and 55minutes after his last break. The data controller had 11years of experience, with four years in the Calgary en route specialty. On the day of the occurrence, he reported for work at 0700 with the incident occurring nine hours after the beginning of his shift and 46minutes after his last break. Cognitive fatigue arises typically as the result of long periods of work involving high levels of information load.2 Generally there are effects on short term memory, the timing of tasks, and attention.3 Both Red Deer sector controllers, as well as the supervisor, considered themselves to be somewhat tired near the end of their shifts because of the cumulative workload and extra vigilance associated with G-8 airspace activity. Flow control is a tool used to reduce air traffic in terminal areas when the demand exceeds or is forecast to exceed system capacity. Two forms of flow control were used on the day of the occurrence in order to meter the traffic in the Calgary terminal area: Air stop, which controls the flow of traffic into the Calgary terminal airspace by placing aircraft in holds outside the terminal area for intervals of up to 20minutes. Ground delays, which space aircraft departures from other airports in order to meter traffic into the terminal area. In the Edmonton ACC, authority to implement flow control was a responsibility of the duty shift manager. En route sector controllers or supervisors were normally consulted regarding initiating or cancelling flow control procedures. The Calgary terminal control coordinator had been delegated the authority to implement tactical flow control, when needed, for Calgary Airport. At 1430, the Calgary Airport was closed to protect the departure of G-8 VIP aircraft. At 1530, after most VIP aircraft had departed, the Calgary terminal control coordinator lifted the closure and initiated flow control to meter arrivals and departures at Calgary. This flow control took the form of ground delays with five-minute intervals between departures of similar aircraft from Edmonton to Calgary, as well as an air stop on traffic destined for Calgary. Four southbound aircraft, including CPB888, were either being held or were being set up for 20-minute holds outside the Calgary terminal shortly before the occurrence. Since the TORON intersection was not available as a holding fix because of weather, the Red Deer radar controller had to develop revised holding fixes. In addition, a 16/17 split was in effect at the request of the Calgary terminal, whereby inbound traffic was generally kept at 17000feet and above and outbound traffic was kept at 16000feet and below. The G-8 coordinator had departed the operations room and the Red Deer sector supervisor was working a control position. Although neither person was available to respond to the Red Deer controller's concern for the building traffic levels, an on-duty shift manager was assigned to traffic management oversight relating to G-8 activities. Preferred IFR Routes listed in the Designated Airspace Handbook TP1820 are described in the Air Traffic Control Manual of Operations (ATC MANOPS) as a method of providing an efficient and orderly management of air traffic normally using the airway system by: guiding pilots in planning their route of flight; minimizing route changes during the operational phase of flight; and aiding in the efficient and orderly management of air traffic using the airway system. Canadian Aviation Regulation (CAR) 602.34 requires that aircraft operate at a cruising altitude or a flight level appropriate to the track as set out in a table accompanying the regulation unless assigned another altitude by ATC. Aircraft flying on tracks between 180 and 359 must cruise at even altitudes (eg: 14000, 16000, 18000, etc.) and aircraft on tracks between 000 and 179 must fly at odd altitudes (eg: 13000, 15000, 17000, etc.) As published in the En route Low Altitude charts published by Natural Resources Canada (LO1 and LO2), for southbound aircraft on V21, even altitudes were appropriate for direction of flight between Fort McMurray and the Edmonton VOR, with odd altitudes appropriate for the remainder of the route to TORON intersection. ATC MANOPS, section 432, states that inappropriate cruising altitudes may be assigned if: no alternative separation minima can be applied; the airspace is structured for one-way traffic flow; or an aircraft requests it because of icing, turbulence, or fuel considerations. None of these criteria applied during this occurrence. Although V21 was a preferred route southbound between Edmonton and Calgary, it was not designated to be structured for one way traffic. ATC MANOPS, section 432.6, specifies that controllers must identify aircraft which are cleared for altitudes inappropriate for the direction of flight when: passing and receiving a control estimate; giving and receiving a radar hand-off; and coordinating with an adjacent sector/unit. Controllers are also required to post warning indicators by circling the altitude in red on the appropriate flight progress strip. During control of CPB888 through the Edmonton terminal and the Red Deer en route sectors, the foregoing actions were not performed while the aircraft was at the altitude inappropriate for direction of flight. Controller performance monitoring and quality assurance were accomplished primarily through semi-annual over the shoulder checks and ongoing, daily supervision. The scheduled checks were conducted by a supervisor using a standardized checklist, and included strip marking practices. Occasionally, reviews of radar and audio tapes were made by NAV CANADA head office personnel as a function of periodic audits. In the Edmonton ACC, it was not a normal management practice to carry out random, unscheduled quality assurance checks of flight progress strips for issuance of appropriate altitudes and proper marking. After the occurrence, a survey of flight progress strips for aircraft transiting from Fort McMurray to Calgary through Edmonton terminal and Calgary en route airspace was carried out. At least six aircraft were cleared through those sectors at inappropriate altitudes over a 24-hour period without meeting the ATC MANOPS criteria for justification and strip marking. NAV CANADA did not have a national policy of random, unscheduled strip examination as part of a quality assurance program. The planning section of the Canada Flight Supplement (CFS), in addition to listing the preferred IFR routes, states In ClassA and ClassB airspace between Edmonton and Calgary, altitudes and flight levels which are not appropriate for the direction of flight may be assigned by ATC at any time to an aircraft operating to a maximum of FL250 on the preferred route. Based in part on the CFS statement, pilots seldom questioned controllers on the issuance of altitudes inappropriate for the direction of flight. The LO1 and LO2 charts contained an error in the depiction of V21. On LO1, even altitudes were shown to be appropriate for aircraft northbound on V21 between the Edmonton VOR and the CALLY intersection. On LO2, even altitudes are shown to be appropriate for the opposite direction on the same section of the airway. Appendix A - Occurrence Diagram 1. All times are mountain daylight time (Coordinated Universal Time minus six hours) unless otherwise noted. 2. Hockey, G.R.J. Changes in Operator Efficiency as a Function of Environmental Stress, Fatigue, and Circadian Rhythms; Boff, K.R., Kaufman, L. and Thomas, J.P., eds. Handbook of Perception and Human Performance: Vol. 11, New York: Wiley, 1986. 3. Stein, Earl S. and Smolensky, Mark W. Human Factors in Air Traffic Control; San Diego: Academic Press, 1998.